The present invention is a solid state electronic communications terminal which effectively combines telephone, data terminal and arithmetic computation capabilities. The terminal device herein referred to as the Electronic Business Telephone (EBT) transmits and receives both voice and data and includes the local capabilities of storing and displaying telephone numbers or other numeric information and performing arithmetic manipulation of entered data.
The two technologies of telephony and data telecommunications have developed more or less independently up to the present time. The interface between the two areas has been broadened to some extent lately in response to the need for communication of digital data between remote locations over conventional telephone common carrier lines. However, these two technologies have been "adapted" to each other's requirements rather than being truly integrated in the form of a totally new terminal device based on an optimized design approach which serves both functions effectively.
For example, various types of modems or acoustic couplers, such as the Western Electric Type 103A Data Set, marketed under the trademark "Data-Phone" by Bell System, have been developed under pressure from users of computer services in order to provide them with remote access to a central data processing installation through existing communications networks. Another typical device of this nature is shown in U.S. Pat. No. 3,583,554, issued to Le Blang, which discloses a portable numeric display device with is acoustically or electromagnetically coupled to a selective tone generating telephone in order to adapt it to be used as a data terminal. Devices of this type are characterized by the common limitation that they act as an external adjunct to a conventional electromechanical telephone which activates or de-activates the standard electromechanical processes of the telephone.
Similarly in the area of electronic desk calculators, it has been suggested to adapt a conventional calculator to include the capability for entry and dialing of telephone numbers. Such an approach is discussed in generalized terms in British Pat. No. 1,179,585, issued to VEB Elektronische Rechenmaschinen which suggests that a "transmission channel" including a code conversion device be interposed between the keyboard entry register of the calculator and the telephone exchange device.
On the other hand, the telephone industry being considerably older and more firmly committed to existing methods and equipment, due in large part to economic considerations and historical inertia, has not effectively applied newly developed technology in computer systems design and microelectronics to its own customer terminal equipment. The three primary developmental stages of telephone equipment have involved the call placement function and are represented in terms of hardware by the crank telephone, the rotary dial telephone and the selective tone generating (e.g. Touch-Tone) telephone. The present invention represents the next evolutionary phase, the electronic telephone.